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Custom Wrench

At work one of the machines that we are in the process of designing had a bolt that was inaccessible with a torque wrench using standard tools. We needed a custom tool to access the bolt so that we could properly torque it down. Using an oxyacetylene torch I bent the handle of the ratcheting combination wrench to make the open end side of the wrench parallel to the ratcheting box end. Next I welded an impact socket on the open end side to allow for access with a 3/8” extension and a torque wrench. I made a 14 mm to 10 mm hex adapter to allow us to use a 14 mm wrench with the 10 mm hex required to tighten the inaccessible M12 bolts, because we were concerned that the M10 ratcheting combination wrench would be too wimpy.

One thing I noticed was that the thinner socket needed more heat than the thicker open end wrench to make them both the same color during welding. I am assuming that this might be because the socket had more carbon than the open end wrench and a higher melting temperature.

Foot-pounds is simply how many pounds of force you apply one foot away. If one is even moderately competent with the math, easy to scale it up or down. Most of the old-time Cat mechanics or JD mechanics, that I knew anyway, didn't even own a torque wrench. Torqued every bolt, even the head bolts, up by feel.

Obviously, I'm just a hack-artist, you shouldn't be listening to anything I say .....

Foot-pounds is simply how many pounds of force you apply one foot away. If one is even moderately competent with the math, easy to scale it up or down. Most of the old-time Cat mechanics or JD mechanics, that I knew anyway, didn't even own a torque wrench. Torqued every bolt, even the head bolts, up by feel.

Attached is a picture with the calculaton for the diminished torque when used with an extension. (Courtesy of Dale M.)

Attached is a picture with the calculaton for the diminished torque when used with an extension. (Courtesy of Dale M.)

Don52,

If the first formula is used, it appears that the output torque is actually increased when using an extension, even though the input torque remains the same. So, it follows... if the input torque at the handle is 150#, and the extension is equal to the length of the wrench (in effect doubling the length), then the output torque is 300#.
Regards,
Goodhand

If the first formula is used, it appears that the output torque is actually increased when using an extension, even though the input torque remains the same. So, it follows... if the input torque at the handle is 150#, and the extension is equal to the length of the wrench (in effect doubling the length), then the output torque is 300#.
Regards,
Goodhand

And that's the whole point of the exercise. One formula says if your wrench is set for 150, you get 300 with the extension. The other formula says if you want 300, then set your wrench to 150. The formulas allow you to substitute different values for your extension length, wrench length, and the desired torque to be applied (which is usually known).